Scientists may have finally solved the 2,200-year-old mystery of Hannibal’s legendary Alpine crossing.
In 218 BC, the young Carthaginian general marched 40,000 men, 7,000 horses, and 37 war elephants across the Alps into Italy to wage war against Rome.
For hundreds of years, historians have struggled to pin down the exact route of military history’s greatest journey.
But now scientists have used the science of elephant athletics to trace Hannibal’s steps through the mountains.
With historical evidence so sparse, researchers used modelling based on modern African elephants to estimate how much energy each possible route would require.
This revealed that the most popular theory, the Col du Clapier route, would have been one of the most arduous options available.
Instead, the researchers found that the most efficient route would have been to take the Col de la Traversette, a mountain pass connecting France and Italy at 9,669 feet (2,947 m).
This would have used between 11 and 19 per cent less energy than the alternative options – making it the most likely path for a pack of exhausted soldiers.
Scientists have revealed the route that Hannibal might have used to cross the Alps in 218 BC, showing that the Col de la Traversette would have been the most efficient route
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Should Hannibal be celebrated as a military genius for risking thousands of lives and animals on such a brutal journey?
Hannibal’s crossing of the Alps is often seen as the climactic moment of the Second Punic War between Carthage and Rome in the third century BC.
Having conquered much of what is now modern-day Spain, the 28-year-old general Hannibal led his army northwards to march on Rome.
Rather than battle through Roman-allied garrisons or risk crossing the Mediterranean Sea where Roman naval forces dominated, Hannibal decided to take his army over the Alps and enter Italy through the Po Valley in the north.
Not prepared for the Carthaginians’ boldness, Rome’s northern forces were defeated by December that year and Hannibal spent the next 15 years rampaging through Italy.
But even the closest contemporary report of this achievement wasn’t written until decades later, and archaeological evidence has remained elusive.
‘The question of Hannibal’s exact route has been debated for generations,’ says co-author Dr Emilio Berti, of the German Centre for Integrative Biodiversity Research.
To try and solve this puzzle, Dr Berti and his co-author used a model that combines body mass and terrain slope to work out how much energy a route would consume.
They used these calculations to work out how efficient each of the four most likely routes through the Alps would be for men, horses, and elephants.
In 218 BC, the young Carthaginian general marched 40,000 men, 7,000 horses, and 37 war elephants across the Alps into Italy to wage war against Rome
Scientists found that the Col de la Traversette would have used between 11 and 19 per cent less energy for the men, horses and elephants than other possible paths
These revealed that the route via the Col de la Traversette is the most efficient path, consuming 5.42 terajoules of energy for the whole army.
That is 11 per cent less than the second best option, going via the Col de Montgenèvre and reaching the Po Valley from Susa, which used 6.02 terajoules.
The route via the Col du Clapier, which had been seen as the most likely choice, was even less efficient – costing 6.28 terajoules.
A proposed route along the Col du Mont Cenis was the least efficient option, at 6.45 terajoules for Hannibal’s entire army.
Dr Berti says: ‘The new analysis does not eliminate all ambiguity, but it does strengthen the case for the Traversette route by demonstrating that it would better accommodate the demands of moving a large army that included elephants through extremely difficult alpine terrain.’
However, even though this route is more efficient than the alternatives, the researchers also showed just how gruelling the march would really be.
Following this route, the men in Hannibal’s army would lose 19 per cent of their body fat reserves.
This, combined with the cold weather and hazardous terrain, could explain the high mortality rate for the human part of the army.
Hannibal’s surprise attack in North Italy allowed him to gain the upper hand over Rome. However, scientists say the crossing consumed 19 per cent of his men’s body fat reserves, leading to high fatalities
The elephants would have handled the crossing better than men due to their large fat reserves and surprisingly good climbing skills, losing just four per cent of their body fat. Pictured: An African elephant demonstrates its climbing ability
The elephants, meanwhile, would have fared much better than you might expect.
According to the researchers’ calculations, the elephants would have lost just four per cent of their fat reserves by the time they reached Northern Italy.
This is partially because elephants naturally have large fat reserves, but also because elephants are far more capable mountaineers than they often get credit for.
In their paper, published in the Proceedings of the National Academy of Sciences, the researchers write: ‘Indeed, in addition to having large fat energy reserves, we now know that elephants move akin to a four-wheel-drive vehicle.
‘This would make them particularly suitable for mountaineering.’
The fact that none of the elephants died during the crossing is a testament to just how tough these animals really are.
However, the fact that all had been left to die by the following winter suggests that Hannibal might have come to regret bringing such enormously expensive war animals with him after all.
THE CARTHAGINANS
Pictured: the location of Carthage, with the extent of the Carthaginian Empire in blue
Ancient Carthage was a Phoenician civilisation centred around Carthage, on the Gulf of Tunis, which was founded by colonists from Tyre in 814 BC.
At its height during the fourth century BC, the city–state became the largest metropolis in the world, with an empire that dominated the western Mediterranean.
It had a mercantile network that extended from northern Europe down to West Africa and across to West Asia.
Far less is known about Carthage’s peoples than those of ancient Rome or Greece, as most indigenous records were destroyed — along with the city — following the Third Punic War in 146 BC.
Their victory in this conflict paved the way for the Roman civilisation to become the dominant power in the Mediterranean.
